The leading cause of death in the United States is heart disease, claiming approximately 24% of all deaths. Coronary artery disease is a condition where coronary arteries narrow due to fatty plaque build up, reducing the blood flow to the heart which can lead to heart failure and death. A minimally invasive procedure called percutaneous coronary intervention (PCI) including balloon and stent angioplasty has been developed to treat coronary artery disease.
There are two major complications associated with PCI: restenosis (renarrowing) and thrombosis (blood clots). Restenosis is caused by a combination of early elastic recoil, negative remodeling, and neointimal formation. Early elastic recoil occurs immediately, and is due to the elastic properties of the arteries. Late lumen loss in balloon angioplasty is caused by neointima formation (tissue in-growth) and negative remodeling (arterial shrinking). In stent angioplasty, a cylindrical scaffold wire mesh (stent) typically made of stainless steel is implanted in the artery to prevent restenosis. These stents prevent elastic recoil and negative remodeling, however, neointimal formation can still lead to restenosis.
Stents have proven to reduce the rates of restenosis more than angioplasty alone. Drug-eluting stents have further reduced restenosis rates, but there is a concern for their ability to prevent late-term thrombosis. New stent materials that can improve these two complications associated with existing coronary stents will be advantageous in stent development.